1. Field of the Invention
The present invention generally relates to sensing devices employing floatation means and, in particular, to such sensing devices as are used for detecting hydrocarbon substances in ground water.
2. Statement of the Prior Art
The wide spread use of fossil fuels in the world today has caused many problems with the pollution of drinking water and drinking water sources. For this reason, sensing devices have been developed for detecting the presence of hydrocarbon containing substances in ground water. One such detecting device is described in U.S. Pat. No. 4,221,125 and employs a semiconductor sensing element mounted on a floatation device for maintaining the sensing element in proximity to the surface of the ground water. Unfortunately, due to the presence of various corrosive chemicals in ground water, which chemicals include hydrocarbon substances, it has been determined that it is important to prevent the deterioration of the sensing device when exposed to such chemical substances. A related sensing device is disclosed in U.S. Pat. No. 4,223,552. However, that device encloses the sensing element in absorbent material, limiting use of the device to a single sensing operation. It has been discovered by a co-inventor of the present invention that the use of a closed cell neoprene rubber called nitrile for the floatation device avoids corrosive and deteriorative effects caused by various substances present in ground water. This discovery is described in the co-pending patent application entitled "Sensing Device" by Ralph A. Perry Ser. No. 197,953 filed Oct. 17, 1980. Prior developments of the electrical connection means for connecting the sensing element to a sensing instrument have only included relatively complicated and expensive to produce coupling assembliges. Therefore, a need exists for a simpler yet reliable electrical connection means.